The downside of marijuana


DEAR DR. DONOHUE: As marijuana smoking is quite popular, I would like to know what effect its smoke has on the lungs of the user. Having been part of the police department and being aware that users inhale and keep the smoke in their lungs for quite a while, it seems that this practice could be damaging. Is a marijuana cigarette more harmful than a nicotine cigarette? — R.M.

ANSWER: It’s almost intuitive that deeply inhaling a substance that has more than 150 compounds in it, as marijuana has, is not going to be a health boon for the lungs. The pleasant feeling, giddiness and relaxation that are the attraction of smoking marijuana come from tetrahydrocannabinol, THC. What the other 149 compounds do isn’t known with great certainty.

Marijuana has three times the tar that cigarettes have. It might lead to lung cancer. That’s an issue that has been speculated about but has never been proven. Marijuana smoke, like cigarette smoke, irritates the airways and, for chronic users, causes a cough and diminished lung capacity. It also causes wheezing and shortness of breath.

Most marijuana smokers smoke fewer marijuana cigarettes than nicotine smokers smoke nicotine cigarettes. That’s one plus for pot.

The long-term consequences of marijuana smoking are destructive to the lungs but apparently less destructive than nicotine smoking, again for the reason that the number of marijuana cigarettes inhaled per day is far less than the number of nicotine cigarettes.

DEAR DR. DONOHUE: My wife has a condition that can be quite embarrassing at times. She frequently gets attacks of sequential yawning. I have measured the period between her yawns at a low of 30 seconds and a high of 90 seconds.

This typically happens when she is in a listening mode, such as at a church service or a meeting or even a party. As you can assume, this is not a life-threatening condition, but it sure is embarrassing. As an observer of many of her incidents, I have not come to the conclusion that boredom causes it. Is there a treatment? — S.S.

ANSWER: As you might imagine, not a whole lot of research has been done on yawning or its causes. Everyone agrees that sleepiness and boredom prompt yawns. However, yawning happens in situations where neither boredom nor sleepiness enters the picture. Athletes, for example, are notorious for yawning before competition, an observation that has no explanation.

Humans aren’t the only ones who yawn. Most animals do so, including birds and fish. I haven’t ever seen a fish yawn, but I am told they do.

Hypotheses for yawning include such things as a need by the brain for more oxygen and a need by the body to get rid of a buildup of carbon dioxide. That sounds farfetched to me. Others claim it cools the brain. Ditto for that. However, it does keep air sacs in the lungs (alveoli) opened, and that enhances the intake of oxygen into the body.

If your wife is aware of her yawning — and she must be, with you timing it — she can stifle a yawn without any harm to herself. Yawning might have become a habit for her.

DEAR DR. DONOHUE: I have enclosed three different X-ray reports. Why is there such difference? Is it possible that one X-ray company is owned by an insurance company? — K.P.

ANSWER: All three read pretty much the same to me. One mentions spondylosis, which is degenerative changes due to arthritis. Another refers to the same process as degenerative osteophytosis. “Osteophytosis” is a word not much used but meaning bony outgrowths seen in arthritis. Retrolisthesis is a slight slipping of one vertebra backward over the vertebra below it. One cites disk narrowing. The others don’t, probably because it’s slight. I think the different words with similar meanings are the reason for your confusion. I never heard of an insurance company owning a radiology practice.

Will you write back with your address in the letter? I want to return your check.

Dr. Donohue regrets that he is unable to answer individual letters, but he will incorporate them in his column whenever possible. Readers may write him or request an order form of available health newsletters at P.O. Box 536475, Orlando, FL 32853-6475. Readers may also order health newsletters from